It's almost impossible to describe Virgil Thomson and Gertrude Stein's "The Mother of Us All" without making it sound precious. Among other things, it is an opera about the life and career of Susan B. Anthony. But such utterly unrelated figures as John Adams, Gen. Grant and Daniel Webster, among others, wander through. And there's Lillian Russell, too.

It sounds like an operatic "Ragtime"--but "The Mother of Us All" is much finer than that.

The only way to understand it is to experience it, especially in a performance that swings and sways with style and verve like the one that opened at the Wolf Trap Barns last night. This production is the one that was such a triumph in New York this year, and it will be repeated tonight and Friday.

What "The Mother of Us All" really adds up to is a sort of sustained whoop of joy and revelry in the spirit--musical and verbal--of the 19th century as reflected through the esthetic prisms of those sophisticated Americans in Paris, Thomson and Stein. The opera finds both of them at their peaks.

The eminent Mr. Thomson, the deft music critic, would no doubt cringe at the phrase "an American classic," but one has the feeling that the eminent Mr. T., the composer, who will be one of this year's Kennedy Center honorees, might find a way to tolerate it. And that's exactly what "The Mother of Us All" is--just as much a classic as the works of Twain, Whitman, or Gershwin.

Stein's text, which she wrote in the last months of her life, somewhat moderates her penchant for abstract wordplay, without being any less brilliant than, say, "Four Saints in Three Acts." She gave Thomson characters that stir the soul. It is as if, at this point in Stein's life, the smouldering intensity that lies beneath that forbidding exterior in the great Picasso painting of her were coming a bit to the surface.

The character of "Susan B," that giant of 19th-century feminism, seems to verge on the autobiographical at times. Several old friends of Stein are among the opera's characters, and persons named "Gertrude S." and "Virgil T." play roles similar to the Stage Manager in "Our Town."

Thomson, who wrote the work in the mid-'40s while he was music critic of The New York Herald Tribune, took the material and made a real opera out of it, full of buoyant, warm melodies that lie beautifully for the human voice. It evokes that same bygone world as Charles Ives, but in an utterly different way--much influenced by the music of Satie. As critic Robert Marx wrote, it is like "a Kansas City Fourth of July parade resonantly marching down the Champs Elyse'es."

Thomson has always set the English language just as unerringly as he writes it. And in this production, diction is remarkable: in the intimate and warm acoustics of Wolf Trap's Barns, hardly a syllable of Stein's verbal melange was missed all evening.

Carmen Pelton plays the title role, and she is wonderfully prim and forbidding in demeanor as Susan. The human side of the famous suffragette develops slowly, mainly in Thomson's music. He writes some truly lovely, and often quite difficult, music for her.

There is the bewitching, and moving, act two duet between Susan and her friend Anne, very nicely sung by Linn Maxwell, on their return from a rally. And, most beautiful of all, there is the grand aria with which the opera ends, in which Susan, long after her death, takes stock of her life while a statue of her is being unveiled.

Thomson takes advantage of this crowd of characters to create some marvelous ensembles, particularly the eloquent and hilarious marriage scene at the end of the first act between Jo the Loiterer and Indiana Elliot. In a whacky way, it reminds one of the marriage scene in "The Marriage of Figaro." Jo and Indiana, two of the opera's most touching characters, are splendidly performed by John Vining and Maxwell, who doubles in the part. (There are 10 singers in 16 roles.)

Avery J. Tracht gives a particularly delightful performance of John Adams, played like a bumpkin in a Viennese operetta. And if you ask what John Adams is doing in an opera about Susan B. Anthony, the only feasible answer is, why not? There are time warps all over the place. At one point Gen. Grant (played by Wayne Turnage) is singing away about Gen. Eisenhower.

The roles of Stein and Thomson are played by Sisu Raiken and Richard Frisch. Constance Fletcher is splendidly done by Kate Hurney. And Sheila Barnes is delightful in the joint roles of Angel More and Lillian Russell.

If "The Mother of Us All" sounds chaotic, the effect is just the opposite. As with most of Thomson's music, it is the essence of conciseness and clarity. The work lasts more than two hours, counting intermission, but it seems to fly by like a breeze.

Thomson's orchestral score is reduced to four players in this version, with much the same cabaret effect that Arena achieved in its recent "Candide." Richard Cordova plays the piano and directs with much brio.

This production, directed by Stanley Silverman, is minimal as far as settings and props go. That is often an advantage in helping reconcile all the contradictions and incongruities of the work. And it fits the stage of the Barns superbly.